Opelucid City is one of the oddest cities in any Pokemon game. For one thing, its appearance varies depending on version. In Black version, you have a futuristic city with little nature, whereas in White version, you have an old-fashioned city which values nature. However, the gym looks almost exactly the same.
When you arrive, you will see Alder, who will take you to a Team Plasma demonstration, similar to the one in Accumula Town. Ghetsis tells the crowd that they should release their Pokemon, and that N is the hero that will save Unova.
You and Alder talk to Drayden and Iris, and eventually you are taken to Drayden's house, where the legend of the two dragon Pokemon of Unova are explained.
The Battle House lets you participate in a Rotation or Triple battle, depending on version.
In White version, Eileen and Lou swap their teams.
The gym here specialises in Dragon-type Pokemon. It uses a puzzle based on huge dragon statues that move their heads based on pressed switches. The gym leader will be Drayden in Black version, and Iris in White, but their teams are exactly the same.
- Leader Drayden/Iris
Your best bet here is an Ice-type Pokemon like Vanilluxe, however Druddigon is equipped with Revenge to deal with this. They all know Dragon Tail, a move which can mess up your team strategy, and Dragon Dance can be used by two of them to quickly raise stats.
After the battle you obtain TM82, which contains Dragon Tail. You also obtain the Legend Badge, your final Unova League badge.
Now, heal up and get ready for your journey to the Pokemon League. It begins on Route 10 to the north of Opelucid City.